Differential bellows control device



y 3, 1950 o. l. STEIGERWALT 2,508,584

DIFFERENTIAL BELLOWS CONTROL DEVICE Filed NOV. 2'7, 1945 2 M k 4 l3 I \1 k 4 l 1 I O I I I O |2 A? I 9 A I I v r 1 1 I7 I 1 7 9 a [8 FIG. 4 F|G.,3

INVENTOR OLIVER LSTEIGERWALT BY WM 2, /wu

ATTORN EY Patented May 23, 1950 UNITED STATES PATENT OFFI C'E DIFFERENTIAL BELLOWS CONTROL DEVICE Oliver; I. Steigerwalt, NiagaraFalls, N. Y., assignor to the United States of America as represented by the. Secretary of War ApplicationNovember 27, 1945, Serial No. 631,191

1 Claim. 1;,

The invention to be; hereinafter described relates to a liquid flow controlled switch.

There, are a great many, automatically actuatecl electric switches for opening'or closing circuits for actuating or, stopping one or another piece of machinery or equipment. Many of them are intricate, delicate and correspondingly difficult to maintain, bulky, or inefficient. The majority depend upon positively acting mechanical devices movingto engage them and throw them into operative or inoperative position for completing or interrupting acircuit or circuits.

The main objects of the present invention are to eliminate or minimize the above and other objections and provide a simple, efilcient, compact, and durable switch operating device automatical ly operable in responseto conditions of fluid current flow in a conduit.

In order to more clearly disclose the construction, operation and use of the invention reference should be had to the accompanying drawings forming part of the present application.

Throughout the several figures of the drawings like reference characters designate the same parts in the diiierent views.

In the drawings:

Fig. 1 is a plan view of the invention;

Fig. 2 is a left-hand side elevation of the device;

Fig. 3 is a right-hand side elevation of Fig. 2; and

Fig. 4 is a view similar to Fig. 1, with the Venturi member and bellowsheadsin section, the switch being omitted.

As a matter of clearness, the circuit-wires of the switch have been omitted from all but one of the views of the drawings.

Referring to the drawings in detail, I indicates a suitable panel or like support on which the several components are mounted and which may, itself, be secured to a wall, post. beam, or any piece of machinery or equipment. Near its opposite ends it carries two hollow plates or chambered heads 2 and 3 each provided with relatively small ports or inlets 4 and-large outlets 5. The outlet 5 from head 2 delivers into the adjacent upper or low pressure bellows 6 while outlet 5 from head 3 delivers into the lower or high pressure bellows l. The two bellows are separate and distinct. There is no passage from-one: to the other or communication between them. Their adjacent ends are, however, connected by a ring or plate 8, a bolt and nut connection being passed through the two adjacent bellows ends and the intervening plate. Plate 8 carries rigidly fixed thereon a radially extending switch actuating lever arm 9 tor a purpose to be later disclosed.

Suitably connected to and carried by the heads 2 and 3 and in position to communicate with ports or inlets l thereof isa water or other liquid supply pipe or main l0 leading from a suitable source of supply and, normally, having acontinuous flow therethrough. The flow is in the direction from head 2 to head 3-. Main I0 is provided with suitable radial bores or openings which, in assembled relation, are aligned with 10 ports or inlets 4.

Main I ii is provided with or'formedi with a Ion-- gitudinally extending. conically' tapered restr-iction of considerable length in the-nature of andoperating as a Venturi passage or tube ll. It is so disposed that its smallest diameter or greatest flow velocity in main It; is-approximately at the point or throat, where the passage in main I0 communicates with port or inlet 4 leading into the chamber of the upper head 2. In the construction shown, thisventuri extends-from that point to a point approximately half way between the heads 2 and 3-at whichpoint it reaches the full diameter of the inside of main- Hi.- It will be noticed'that the effective high pressure portion of this Venturi tube increases in diameter in the direction of flow, or down stream,- which'is an opposite disposition to conventional'usage in which the restriction increases in the directionof flow.

As is well known, there will be lowpressure at the restricted end in the area of. the inlet 4.to.- head '3 and its bellows 6 and higherpressureat:

and beyond the larger downstream, end; ofthe.

venturi, including the area around vtheinlet to head 3 and its bellows 1. That will-result in a correspondingexpansion of bellows! relative-tobellows 6 with resulting movement of plate 8 andarm 9 toward upper head 2. Elastic. quality of the bellows material, as is usual, causes the. plate 8 and arm ii to assumeaneutral-positionz,along the axis of the bellows when pressuresare equal in the two. bellows. Should, the flow in main l0 cease or drop below a predetermined point the.

pressures in the two bellows become equalized and the plate 8 and arm 9:return to neutral or normal position. crease of pressure from thenormal working condition in bellows 6 and may be considered an This is equivalentto an in:-

and well known construction and operation. Preferably, the block or unit of the switch is pivoted at one end to a small plate l3 by a bolt or the like l4, the plate I3 being secured to the lower head 3 by screws or other suitable means. The opposite end of switch unit 12 is adjustably connected to plate l3 by a. similar bolt l3 playing in an arcuate slot 15 in said plate. By swinging l2 pivotally about l3 until it reaches the desired position and then tightening bolt I3 to anchor l2 in that position, the actuating pin, push button or the like it of the switch may be held at the exact predetermined point for the desired cooperation with arm 9. For quick determination of that point, an adjustable stop is provided in the form of a threaded rod or set screw I! carried in and adjustable through a short arm I 8 extending from the panel I above the movable end of unit switch l2. Thus, when the desired position of i2 has once been determined, screw 11 will be turned down to cause the arm 9 to just engage the push button it but not sufiiciently to operate the switch, and secured there by the usual lock nut. Th n upward movement of i2 beyond that point will be prevented.

To avoid possible excessive upward movement of the bellows units a stop bar 59 is provided projecting from panel i into the upward path of lever 9 and disposed above the arm and practically in engagement with it when the arm is in its normal position during regular flow conditions through the device.

Any desired circuit for any purpose may be controlled by the switch l2, all as will be readily understood and need not be further detailed here. Likewise, the switch elements may be so arranged as to either make or break the circuit upon movement of the arm 9 and, of course, the movement chosen for such operation may be either to the position corresponding to normal flow or to the position corresponding to deficient flow or clogged condition.

It is thought that the construction, operation and use of the invention will be clear from the preceding detailed description.

It will be seen that in the specific arrangement of Fig. l, as long as liquid flows through the main ID at or above a predetermined minimum, the difference in pressure in the two bellows will cause the bellows i to over-balance the force exerted in the bellows 6 and the switch will be kept open. Under exceptional condition, should the fluid flow velocity in the main I fall below the minimum predetermined, however, the difference in pressures will be lowered, the low pressure bellows B will develop a greater pressure in relation to that manifest in bellows l, and by the consequent expansion of bellows B the switch will be closed. This exceptional operation may be utilized to sound an alarm or to operate safety or corrective devices. Likewise, if stoppage of the throat of the Venturi tube should occur upstream from the inlet 4, the device will operate to effect the necessary safety operation as last described. Also, if the throat should become so clogged downstream from its port 4, that full pressure is admitted at head 2 only, and partial or complete cut off from head 3 occurs, a very positive emergency operation by bellows 6 would occur. If prior customary arrangements of differential bellows inlet connections in relation to fluid flow in Venturi tubes were used in my device however, a stoppage at the upstream end of the throat would merely increase the pressure in the high pressure bellows against the backoff stop screw ll, so that the switch would simply continue open and no corrective action would occur.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

In control apparatus for liquid supply systems and responsive to exceptional low rate liquid current flow or stoppage, wherein said apparatus comprises a liquid conducting conduit, means responsive to differences between the static pressure in the conduit and a pressure resultant of the velocity head of liquid flowing longitudinally in the conduit, said last named means comprising two coaxial opposed bellows having distal closed stationary sides and having mutually connected proximal closed sides and a lateral operating arm commonly movable along the bellows axis, means connecting the interiors of the bellows respectively with the said conduit, one constructed to transmit at least static conduit pressure, and the other responsive to transmit a velocity head pressure difference in the conduit, a movable control device having a normal operative and an alternative emergency position and cooperatively associated with the said operating arm in a position to be moved by the latter to said emergency position on movement of the said operating arm beyond a predetermined limit in one direction, and to be in said normal position at positions of the operating arm in its range of movement toward the opposite extreme from said limit; the improvement wherein said control device comprises a support fixed in relation to the said distal sides of said bellows and including a plate parallel to said axis distant from said operating arm and adjacent the line of movement of the latter, a case pivoted on said plate, its pivot spaced from the line of movement of said operating arm, a releasable clamping means coengaged between the plate and case operable at will to secure the case in adjusted positions on the plate, said control device including an operating membr movable on said case in a direction generally coincident with said line of movement of the operating arm, said operating member having a normal position relative to the case extended toward the operating arm and yieldable thereto to an emergency control position by said arm, at a predetermined extreme position of said arm in one direction.

OLIVER I. STEIGERWALT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,847,086 Gargan Mar. 1, 1932 1,999,080 Borden Apr. 23, 1935 2,239,438 Cockrell Apr. 22, 1941 2,275,866 Runaldue Mar. 10, 1942 

